Train working diagram (TWD) plays a very important role in railway transportatio n, and it is the synthetic plan and foundation of railway transport organization .TWD worked out with computer is a practical and diffic...Train working diagram (TWD) plays a very important role in railway transportatio n, and it is the synthetic plan and foundation of railway transport organization .TWD worked out with computer is a practical and difficult project, which must b e solved as early as possible. Through many years research and practice,TWD work ed out with computer makes great progress not only in theory but also in practic e, which breaks into several periods, such as double track line,single track li ne,railway terminal area and railway network. Jing—Hu high-speed railway line, being programmed and built in the Tenth ″Fiv e Years Plan″, will take the mode of high-speed train and middle-speed train sharing high-speed railway line at beginning. So this results in big problem in theory and method of TWD between high-speed railway line and the existing rail way. Based on analyzing production and literatures of China and overseas about T WD of high-speed railway line and the existing railway, this paper establishes the theory of TWD of high-speed and middle-speed train using the same high-sp eed railway network train working diagram (HSRNTWD) .The main contents of this p aper are: (1) This paper analyzes and summarizes production and existing problems of TWD o f high-speed railway line and the existing railway in China and abroad. It desc ribes the differences and common grounds between TWD of the existing railway and high-speed railway line from many core problems such as aim, order and policy of TWD. (2) Based on the transportation mode of high-speed railway line and absorbed th e experience of TWD of the existing railway, this paper puts forward fundamental theory of TWD of high-speed railway line based on railway network, discusses a im, order and hierarchy of TWD of high-speed railway line. (3) This paper establishes the theory of high-speed railway line based on railw ay network from microscopic layer and macroscopic layer. Macroscopic layer is us ed to describe the network structure and relation of railway line, and calculate s the running path of high-speed train and middle-speed train; in microscopic layer, station plane diagram is made up of track circuit, turnout, curve, cross -over, main line or serial number of the station track center. Microscopic laye r is used to calculate and describe the train arriving route, departing route, p assing route, parallel route and conflicting route and so on. (4) Based on analyzing the scope of rational time for train departure and arriva l, this paper brings forward a method to calculate and decide the rational scope of time for departure and arrival of the cross-line middle-speed train. (5) Based on the theory of HSRNTWD, aims at the best convenience, best service f or passengers and good running order for train, this paper establishes a mathema tic model of TWD of high-speed train and middle-speed train running on Jing—H u high-speed railway line, and designs algorithm of FCSFQYGDPUF for this model. (6) For the sake of advancing equilibrium indices of TWD of high-speed railway line, this paper builds a mathematic model to get an initial plan of TWD of high -speed railway line for distributing points and designs an application algorith m of DCKDCRF to seek initial time plan of departure and arrival of high-speed t rain and middle-speed train sharing the Jing—Hu high-speed railway line. (7) For the aim of optimizing the quality of TWD of high-speed railway line, th is paper establishes the mathematical theory of stations lines of high-speed ra ilway line and designs the algorithm of ZXBLBHF to seek the answer to mathematic model. (8) This paper analyzes the running characteristics of high-speed train under t he situation of moving different distances and the use mode of EMU on the high- speed railway, and discusses several modes of integration between EMU and high- speed train, and builds a mathematic model to minimize total detention time of E MU; based on the study of locomotive facilities on the high-speed railway and t he mode of middle-speed locomotive routing, this展开更多
Opportunistic Routing (OR) involves multiple forwarding candidates to relay packets by taking advantage of the broadcast nature and multi-user diversity of a wireless medium. Compared with Traditional Routing (TR), OR...Opportunistic Routing (OR) involves multiple forwarding candidates to relay packets by taking advantage of the broadcast nature and multi-user diversity of a wireless medium. Compared with Traditional Routing (TR), OR is more suitable in the case of an unreliable wireless link and can evidently improve the end-to-end throughput of Wireless Mesh Networks (WMNs). In this paper, we focus on OR in Multi-Radio Multi-Channel WMNs (MRMC-WMNs). This problem has not been well examined and is considerably more challenging than the OR in single-radio wireless networks considered in the existing literature. First, we validate the advantage of OR in MRMC-WMNs. Second, we propose Low-complexity Channel Assignment for Opportunistic Routing (LcCAOR), which assigns channels to flows according to the interference state of every node. Third, we implement the LcCOAR in a fully distributed manner. The simulation result shows that compared with OR in Single-Radio Single-Channel WMNs (SRSC-WMNs), the proposed OR can significantly enhance the throughput to 87.11% and 100.3% in grid and tree WMNs, respectively.展开更多
Wireless Mesh Network has drawn much attention due to wide area service coverage with low system cost and being easy to install.However,WMN suffers from high bit error rate,which provides different link capacity among...Wireless Mesh Network has drawn much attention due to wide area service coverage with low system cost and being easy to install.However,WMN suffers from high bit error rate,which provides different link capacity among wireless mesh routers.The conventional routing metrics select the path based on link quality.The link with the best quality is preferred as the data transmission path,and thus all nodes likely select the same link,which leads to network performance degradation.This paper proposes a routing metric that considers the available bandwidth and the number of nodes suffering congestion in the path.It is confirmed that the proposed method provides higher network performance of reduced delay,reduced packet loss and increased throughput than conventional routing metrics.展开更多
As an extension of wireless ad hoc and sensor networks, wireless mesh networks(WMNs) are employed as an emerging key solution for wireless broadband connectivity improvement. Due to the lack of physical security guara...As an extension of wireless ad hoc and sensor networks, wireless mesh networks(WMNs) are employed as an emerging key solution for wireless broadband connectivity improvement. Due to the lack of physical security guarantees, WMNs are susceptible to various kinds of attack. In this paper, we focus on node social selfish attack, which decreases network performance significantly. Since this type of attack is not obvious to detect, we propose a security routing scheme based on social network and reputation evaluation to solve this attack issue. First, we present a dynamic reputation model to evaluate a node's routing behavior, from which we can identify selfish attacks and selfish nodes. Furthermore, a social characteristic evaluation model is studied to evaluate the social relationship among nodes. Groups are built based on the similarity of node social status and we can get a secure routing based on these social groups of nodes. In addition, in our scheme, nodes are encouraged to enter into multiple groups and friend nodes are recommended to join into groups to reduce the possibility of isolated nodes. Simulation results demonstrate that our scheme is able to reflect node security status, and routings are chosen and adjusted according to security status timely and accurately so that the safety and reliability of routing are improved.展开更多
文摘Train working diagram (TWD) plays a very important role in railway transportatio n, and it is the synthetic plan and foundation of railway transport organization .TWD worked out with computer is a practical and difficult project, which must b e solved as early as possible. Through many years research and practice,TWD work ed out with computer makes great progress not only in theory but also in practic e, which breaks into several periods, such as double track line,single track li ne,railway terminal area and railway network. Jing—Hu high-speed railway line, being programmed and built in the Tenth ″Fiv e Years Plan″, will take the mode of high-speed train and middle-speed train sharing high-speed railway line at beginning. So this results in big problem in theory and method of TWD between high-speed railway line and the existing rail way. Based on analyzing production and literatures of China and overseas about T WD of high-speed railway line and the existing railway, this paper establishes the theory of TWD of high-speed and middle-speed train using the same high-sp eed railway network train working diagram (HSRNTWD) .The main contents of this p aper are: (1) This paper analyzes and summarizes production and existing problems of TWD o f high-speed railway line and the existing railway in China and abroad. It desc ribes the differences and common grounds between TWD of the existing railway and high-speed railway line from many core problems such as aim, order and policy of TWD. (2) Based on the transportation mode of high-speed railway line and absorbed th e experience of TWD of the existing railway, this paper puts forward fundamental theory of TWD of high-speed railway line based on railway network, discusses a im, order and hierarchy of TWD of high-speed railway line. (3) This paper establishes the theory of high-speed railway line based on railw ay network from microscopic layer and macroscopic layer. Macroscopic layer is us ed to describe the network structure and relation of railway line, and calculate s the running path of high-speed train and middle-speed train; in microscopic layer, station plane diagram is made up of track circuit, turnout, curve, cross -over, main line or serial number of the station track center. Microscopic laye r is used to calculate and describe the train arriving route, departing route, p assing route, parallel route and conflicting route and so on. (4) Based on analyzing the scope of rational time for train departure and arriva l, this paper brings forward a method to calculate and decide the rational scope of time for departure and arrival of the cross-line middle-speed train. (5) Based on the theory of HSRNTWD, aims at the best convenience, best service f or passengers and good running order for train, this paper establishes a mathema tic model of TWD of high-speed train and middle-speed train running on Jing—H u high-speed railway line, and designs algorithm of FCSFQYGDPUF for this model. (6) For the sake of advancing equilibrium indices of TWD of high-speed railway line, this paper builds a mathematic model to get an initial plan of TWD of high -speed railway line for distributing points and designs an application algorith m of DCKDCRF to seek initial time plan of departure and arrival of high-speed t rain and middle-speed train sharing the Jing—Hu high-speed railway line. (7) For the aim of optimizing the quality of TWD of high-speed railway line, th is paper establishes the mathematical theory of stations lines of high-speed ra ilway line and designs the algorithm of ZXBLBHF to seek the answer to mathematic model. (8) This paper analyzes the running characteristics of high-speed train under t he situation of moving different distances and the use mode of EMU on the high- speed railway, and discusses several modes of integration between EMU and high- speed train, and builds a mathematic model to minimize total detention time of E MU; based on the study of locomotive facilities on the high-speed railway and t he mode of middle-speed locomotive routing, this
基金supported by the National Basic Research Program of China （973） under Grant No.2012CB315801 the National Natural Science Foundation of China under Grants No.61003305,No.61173167,No.61173168,No.61070194 the Information Security Industrialization Fund from the National Development＆Reform Commission of China （NDRC） under Grant No.NDRC[2009]1886
文摘Opportunistic Routing (OR) involves multiple forwarding candidates to relay packets by taking advantage of the broadcast nature and multi-user diversity of a wireless medium. Compared with Traditional Routing (TR), OR is more suitable in the case of an unreliable wireless link and can evidently improve the end-to-end throughput of Wireless Mesh Networks (WMNs). In this paper, we focus on OR in Multi-Radio Multi-Channel WMNs (MRMC-WMNs). This problem has not been well examined and is considerably more challenging than the OR in single-radio wireless networks considered in the existing literature. First, we validate the advantage of OR in MRMC-WMNs. Second, we propose Low-complexity Channel Assignment for Opportunistic Routing (LcCAOR), which assigns channels to flows according to the interference state of every node. Third, we implement the LcCOAR in a fully distributed manner. The simulation result shows that compared with OR in Single-Radio Single-Channel WMNs (SRSC-WMNs), the proposed OR can significantly enhance the throughput to 87.11% and 100.3% in grid and tree WMNs, respectively.
基金supported by the ubiquitous Computing and Network(UCN)Projectthe Ministry of Knowledge and Econ-omy(MKE)Knowledge and Economy Frontier R&DProgramin Korea as a result of UCN′s subproject10C2-C1-20Ssupported by the MKE(The Ministry of Knowledge Economy),Korea,under the Convergence-ITRC(Convergence Infor mation Technology Research Center)support program(NIPA-2011-C6150-1101-0004)
文摘Wireless Mesh Network has drawn much attention due to wide area service coverage with low system cost and being easy to install.However,WMN suffers from high bit error rate,which provides different link capacity among wireless mesh routers.The conventional routing metrics select the path based on link quality.The link with the best quality is preferred as the data transmission path,and thus all nodes likely select the same link,which leads to network performance degradation.This paper proposes a routing metric that considers the available bandwidth and the number of nodes suffering congestion in the path.It is confirmed that the proposed method provides higher network performance of reduced delay,reduced packet loss and increased throughput than conventional routing metrics.
基金supported in part by National Natural Science Foundation of China(Grant Nos.61302071,61471109,61502075)Fundamental Research Funds for the Central Universities(Grant Nos.N150404015,DUT15QY06,DUT15RC(3)009)+2 种基金China Postdoctoral Science Foundation Funded Project(Grant No.2015M580224)Liaoning Province Doctor Startup Fund(Grant No.201501166)State Key Laboratory for Novel Software Technology,Nanjing University(Grant No.KFKT2015B12)
文摘As an extension of wireless ad hoc and sensor networks, wireless mesh networks(WMNs) are employed as an emerging key solution for wireless broadband connectivity improvement. Due to the lack of physical security guarantees, WMNs are susceptible to various kinds of attack. In this paper, we focus on node social selfish attack, which decreases network performance significantly. Since this type of attack is not obvious to detect, we propose a security routing scheme based on social network and reputation evaluation to solve this attack issue. First, we present a dynamic reputation model to evaluate a node's routing behavior, from which we can identify selfish attacks and selfish nodes. Furthermore, a social characteristic evaluation model is studied to evaluate the social relationship among nodes. Groups are built based on the similarity of node social status and we can get a secure routing based on these social groups of nodes. In addition, in our scheme, nodes are encouraged to enter into multiple groups and friend nodes are recommended to join into groups to reduce the possibility of isolated nodes. Simulation results demonstrate that our scheme is able to reflect node security status, and routings are chosen and adjusted according to security status timely and accurately so that the safety and reliability of routing are improved.
